Performance of the MP570T pulse oximeter in volunteers participating in the controlled desaturation study: a comparison of seven probes

Background@#The performance of the pulse oximeter was evaluated based on the ISO 80601-2-61:2011 (E) guidelines. This study aimed to determine whether the various finger probes of the MP570T pulse oximeter (MEK-ICS Co., Ltd., Korea) would provide clinically reliable peripheral oxygen saturation (SpO2) readings over a range of 70100% arterial oxygen saturation (SaO2) during non-motion conditions. @*Methods@#Each volunteer (n = 12) was connected to a breathing circuit for the administration of a hypoxic gas mixture. For frequent blood sampling, an arterial cannula was placed in a radial artery. The following seven pulse oximeter probes were simultaneously attached to each volunteer’s fingers: (1) WA-100 reusable finger probe (MEDNIS Co., Ltd., Korea), (2) MDNA disposable finger probe (MEDNIS Co., Ltd.), (3) IS-1011 disposable finger probe (Insung Medical Co., Ltd., Korea), (4) CJ340NA disposable finger probe (CHUN JI IN Medical Co., Ltd., Korea), (5) NellcorTM OxiMax DS-100A reusable finger probe (Medtronic, USA), (6) NellcorTM OxiMax MAX-N disposable finger probe (Medtronic), and (7) OXI-PRO DA disposable finger probe (Bio-Protech Inc., Korea). @*Results@#A total of 275 SpO2-SaO2 pairs were included in the analysis. The accuracy of the root mean square (Arms) of each probe was 2.83%, 3.98%, 3.75%, 6.84%, 3.43%, 5.17%, and 3.84%, respectively. @*Conclusions@#The MP570T pulse oximeter with WA-100 reusable, MDNA disposable, IS-1011 disposable, NellcorTM OxiMax DS-100A reusable, and OXI-PRO DA disposable finger probes meets an acceptable standard of SpO2 accuracy under non-motion conditions.

Quantitative analysis of the effect of fraction ofinspired oxygen on peripheral oxygen saturation inhealthy volunteers

Background@#The international organization for standardization (ISO) 80601-2-61 dictates that the accuracy ofa pulse oximeter should be assessed by a controlled desaturation study. We aimed to characterize the relationshipbetween the fraction of inspired oxygen (FiO2) and peripheral oxygen saturation (SpO2) using a turnover modelby retrospectively analyzing the data obtained from previous controlled desaturation studies. @*Materials and Methods@#Each volunteer was placed in a semi-Fowler’s position and connected to a breathingcircuit to administer the hypoxic gas mixture containing medical air, oxygen, nitrogen, and carbon dioxide.Volunteers were exposed to various levels of induced hypoxia over 70-100% arterial oxygen saturation (SaO2).The study period consisted of two rounds of hypoxia and the volunteers were maintained in room air betweeneach round. FiO2 and SpO2 were recorded continuously during the study period. A population pharmacodynamicanalysis was performed with the NONMEM VII level 4 (ICON Development Solutions, Ellicott City, MD,USA). @*Results@#In total, 2899 SpO2 data points obtained from 20 volunteers were used to determine the pharmacodynamiccharacteristics. The pharmacodynamic parameters were as follows: kout = 0.942 1/min, Imax = 0.802, IC50 =85.3%, γ = 27.3. @*Conclusion@#The changes in SpO2 due to decreases in FiO2 well explained by the turnover model with inhibitoryfunction as a sigmoidal model.

Pharmacodynamic Analysis of the Influence of Propofol on Left Ventricular Long-Axis Systolic Performance in Cardiac Surgical Patients

BACKGROUND: Propofol induced a decline in the left ventricular (LV) systolic performance in non-cardiac surgery. We tested the hypothesis that propofol decreased the LV contractile function by dose dependent manner in cardiac surgery patients. METHODS: Anesthesia was maintained with target-controlled infusions of propofol and remifentanil in cardiac surgery patients. With a fixed effect-site concentration (Ce) of remifentanil (20 ng/mL) after sternotomy, the Ce of propofol was adjusted to maintain a Bispectral index of 40–60 (Ce1). Mitral annular Doppler tissue image tracings and other echocardiographic variables, including end-diastolic and end-systolic volumes, stroke volume, and mitral inflow pulse wave Doppler profile at Ce1, were recorded using transesophageal echocardiography. Echocardiographic recordings were repeated after the Ce-values of propofol were doubled and tripled at 10-minute intervals (defined as Ce2 and Ce3, respectively). Serial changes in echocardiographic variables for each Ce of propofol were assessed using generalized linear mixed effect modeling. The pharmacodynamic relationship between the Ce of propofol and peak systolic mitral annular velocity (Sm) was analyzed by logistic regression using non-linear mixed effect modeling (NONMEM). RESULTS: Means of Ce1, Ce2, and Ce3 were 0.8, 1.6, and 2.4 μg/mL, respectively, and their means of Sm (95% confidence interval) were 9.7 (9.3–10.2), 8.7 (8.2–9.1), and 7.5 cm/sec (7.0–8.0), respectively (P < 0.01). Ce values of propofol and Sm showed a significant inter-correlation and predictability (intercept, 10.8; slope–1.0 in generalized mixed linear modeling; P < 0.01). Ce values producing 10% and 20% decline of Sm with 50%-probability were 1.4 and 2.1 μg/mL, respectively. CONCLUSION: Propofol reduces LV systolic long-axis performance in a dose-dependent manner. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01826149

Unexpected anesthetic leakage from a damaged O-ring on the Selectatec back bar: A case report

The Selectatec mounting system was devised to provide easy and quick on-site fitting of various vaporizers for the anesthetic machine. However, a quick changing system for the vaporizer can also damage the O-ring due to friction between the vaporizer and the Selectatec back bar. We herein report a case of an unexpected anesthetic gas leakage from a damaged O-ring on the Selectatec back bar, which resulted from exchanging the vaporizers between two operations. In cases using the Datex Ohmeda machine, it is not easy to detect leakages from the vaporizers because of the location of the check valve near to the fresh gas outlet. This complicates the use of the positive pressure leakage test to detect a low pressure system leakage on the Selectatec back bar. We recommend the preanesthetic negative pressure or low-flow leakage test to detect a low pressure leakage when exchanging vaporizers on the Selectatec system.

Sudden cardiovascular collapse caused by severe anaphylaxis after cisatracurium use: a case report / 대한마취과학회지

Kounis syndrome is an acute coronary syndrome concurrently occurs with allergic or hypersensitivity reactions. In patient with this syndrome, inflammatory mediators released due to an allergic reaction implicate to induce coronary artery spasm and atheromatous plaque rupture. We describe a patient with coronary artery disease who developed acute perioperative myocardial infarction leading to cardiac arrest after the anaphylactic reaction to cisatracurium, which led to a suspicion of Kounis syndrome. Anesthesiologists should be aware that anaphylaxis or allergic reactions can progress to acute coronary syndrome, thereby significantly change the course of the disease.

Anesthetic management of a patient with prune-belly syndrome : A case report

Prune-belly syndrome is characterized by absent abdominal wall musculature with wrinkled overlying skin, urinary tract dilatation and cryptorchidism. Prune-belly syndrome is also associated with diseases of the respiratory, cardiovascular, skeletal, gastrointestinal and central nervous system. Because the congenital disease is uncommon, it is difficult to collect the information of anesthetic management of prune-belly syndrome. We report a case of 4 year-old-boy with prune-belly syndrome who underwent abdominoplasty and Mitrofanoff operation under general anesthesia.

The effect of mitochondrial adenosine triphosphate-sensitive potassium (K(ATP)) channel blocker on ischemic preconditioning in hypoxic-ischemic brain injury model of neonatal rat / 대한마취과학회지

BACKGROUND: A brief episode of cerebral ischemia confers transient ischemic tolerance to a subsequent ischemic challenge that is otherwise lethal to them. This study was purposed to evaluate the effect of mitochondrial adenosine triphosphate-sensitive potassium (KATP) channel blocker on ischemic preconditioning in hypoxic-ischemic brain injury model of neonatal rat. METHODS: Seven-day old Sprague-Dawley rat pups were used. The rats were divided into five groups; control group (n = 91), pretreatment hypoxic preconditioning group (n = 43), pretreatment ischemic preconditioning group (n = 52), hypoxic preconditioning group (n = 39), and ischemic preconditioning group (n = 51). Rats in the pretreatment hypoxic preconditioning group and pretreatment ischemic preconditioning group were treated by an intraperitoneal injection with 5-hydroxydecanoate (60 mg/kg). Thirty minutes after injection, right common carotid artery was temporarily occluded for ten minutes in pretreatment ischemic preconditioning group. Rats in the pretreatment hypoxic preconditioning group and hypoxic preconditioning group underwent hypoxia (8% oxygen/92% nitrogen) for four hours. Twenty-four hours after the preconditioning, rats from all groups were exposed to right common carotid artery ligation followed by 2.5 hour hypoxia. On the 1st day after hypoxic-ischemic brain injury, terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling (TUNEL) reaction was evaluate as apoptotic markers and triphenyl tetrazolium chloride (TTC) was done to measure necrotic tissue. All rats were sacrificed 2 weeks after hypoxic-ischemia brain injury and the brains were examined for morphologic study. RESULTS: There were no differenced in survival rate, infarct area, number of TUNEL positive cells and morphologic score either between hypoxic preconditioning group and pretreatment hypoxic preconditioning group or between ischemic preconditioning group and pretreatment ischemic preconditioning group. CONCLUSIONS: The results suggests that mitochondrial K(ATP) channel blocker, 5-hydroxydecanoate, does not change hypoxic-ischemic preconditioning in the neonatal rat.

The Protective Effect of Ischemic and Hypoxic Preconditioning on Hypoxic-ischemic Brain Injury in the Neonatal Rat: 1H Magnetic Resonance Spectroscopic Study / 대한마취과학회지

BACKGROUND: A brief episode of cerebral ischemia confers transient ischemic tolerance to a subsequent ischemic challenge. We examined the effect of ischemic and hypoxic preconditioning in the neonatal rat. METHODS: Seven-day old Sprague-Dawley rat pups were divided into three groups:control (n = 53), ischemic preconditioning (n = 51), and hypoxic preconditioning (n = 48). For ischemic preconditioning, the right common carotid artery was occluded for 10 min. Rats in the hypoxic preconditioning group were kept under hypoxic (8% oxygen/92% nitrogen) conditions for 4h. Twenty-four hours after the preconditioning, rats from all groups were exposed to the right common carotid artery ligature, followed by 2.5 h of hypoxia. Lipid/N-acetyl aspartate (Lip/NAA) and lipid/creatine (Lip/Cr) ratios from 1H MR spectroscopy and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) were evaluated as measures of apoptosis 1 and 7 days after hypoxic-ischemic injury. RESULTS: In the ischemic and hypoxic preconditioning groups, the Lip/NAA and Lip/Cr ratios and the numbers of TUNEL-positive cells were significantly lower than those in the control group (P < 0.05), but there were no significant differences between the two preconditioning groups. CONCLUSIONS: These results suggest that ischemic and hypoxic preconditioning in the neonatal rat attenuate the apoptosis that is caused by hypoxic-ischemic brain injury.

Validity of Heart Rate Variability Using Poincare Plot for Assessing Vagal Tone during General Anesthesia / 대한마취과학회지

BACKGROUND: A poincare plot of the heart rate variability (HRV) allows for the quantitative display of the vagal tone in conscious humans. However, relatively little is known about standard deviation 1 (SD1) from the poincare plot reflecting the vagal tone and correlating with the high frequency (HF) spectral power of the HRV during general anesthesia. Thus, the association of SD1 from the poincare plot was examined, along with the HF spectral power of the HRV during general anesthesia. METHODS: Beat-to-beat electrocardiograms were recorded for 5 min in 23 patients (isoflurane group, n = 13; sevoflurane group, n = 10) before, during and after general anesthesia. The low frequency (LF) and HF spectral powers, the LF/HF ratio of the HRV and the SD1 and standard deviation 2 (SD2) from the poincare plot were calculated. RESULTS: Both the HF spectral power of the HRV and SD1 from the poincare plot were reduced following general anesthesia, but recovered thereafter. The recovery of both the HF spectral power and SD1 from the poincare plot in the sevoflurane group was faster than those in the isoflurane group. There were strong correlations between the HF spectral power and SD1 before, during and after anesthesia. CONCLUSIONS: These data suggest that the SD1 from the poincare plot is a useful and valid parameter for analysis of the vagal tone during general anesthesia.

Anesthesia in a Patient with Brugada Syndrome without a Characteristic ECG Pattern: A case report / 대한마취과학회지

Brugada syndrome is characterized by an ECG pattern of right bundle branch block and ST segment elevation in right precordial leads (V1 to V3), without structural heart disease. However, these ECG manifestations transiently normalize in up to 40% of cases. Brugada syndrome is responsible for up to one half of all sudden cardiac deaths in young adults and they may be worsened by beta blockers. We present the anesthetic management of a patient with Brugada syndrome without the characteristic ECG pattern.

Effect of Inducible Nitric Oxide Synthase Inhibitor on Apoptosis in Hypoxic-Ischemic Injury of the Neonatal Rat Brain: 1H Magnetic Resonance Spectroscopy Study / 대한마취과학회지

BACKGROUND: Inducible nitric oxide synthase (iNOS) is expressed during the late stage of ischemia and may play an important role in the delayed progression of ischemic brain injury. This study was conducted to investigate the effect of N-(3-[aminomethyl] benzyl] acetamidine (1,400 W), a selective inhibitor of iNOS on hypoxic ischemic injury in a neonatal rat model. METHODS: Seven-day old Sprague-Dawley rats were used. The right common carotid artery was ligated under halothane anesthesia. Three 3 hours after recovery, animals were exposed to 8% oxygen in 92% nitrogen. The treatment group (n = 14) received 7 intraperitoneal injection of 20 mg/kg of 1,400 W. The first dose was given 18 hours after the injury and interval between injections was 8 hours. The control group (n = 13) did not receive 1,400 W. The degree of ischemic damage and apoptosis were evaluated 3 days after injury by 1H magnetic resonance spectroscopy (MRS) and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling (TUNEL) staining. The authors obtained Lipid/N-acetyl aspartate (Lip/NAA) and lipid/ creatine (Lip/Cr) ratios as apoptotic markers via 1H MRS, and counted the apoptotic cell number by TUNEL staining in the right hemisphere. Data were analyzed using the unpaired t-test. RESULTS: There were no significant differences in the Lip/NAA or Lip/Cr ratios of the 2 groups, and no significant differences were found in terms of the number of TUNEL positive cells between 2 groups, either. CONCLUSIONS: The iNOS inhibitor investigated did not show protective effects against delayed neuronal damage and apoptosis after the hypoxic-ischemic injury in newborn rats, at least during the 3 days following injury. Our results suggest that NO has different roles in cerebral hypoxia-ischemia according to the stage of neonatal cerebral development.

The Effects of Perfluorocarbon on Respiratory Mechanics and Pulmonary Gas Exchange with Methacholine-induced Bronchoconstriction in Cats / 대한마취과학회지

BACKGROUND: Perfluorocarbon (PFC) liquids have high oxygen carrying capacity and relatively low surface tension allowing them to spread evenly through the diseased lung, especially in the case of adult respiratory distress syndrome. But few studies have demonstrated the effects of PFC on a bronchoconstriction model. The aim of this study was to investigate the effects of PFC on pulmonary mechanics and gas exchange in methacholine-induced bronchoconstricted cats using a flow interruption technique. METHODS: Twenty male cats were divided into four groups; control group (group C, n = 5), PFC group (group P, PFC 5 ml/kg, n = 5), methacholine group (group M, 25 microgram/kg/min, n = 5), PFC and methacholine group (group MP, n = 5). Respiratory pressure using a flow interruption technique was measured immediately after stabilizing the heart rate and blood pressure 0, and 15, 30 and 60 min after the start of the intratracheal administration of PFC and/or methacholine infusion, depending on the group. Arterial blood gas analysis was done to compare arterial partial oxygen pressure among the groups at the time of measuring the pressure values. The pressure data was transferred to a personal computer and analyzed using ANADAT software program. Respiratory, airway and tissue viscoelastic pressure were calculated. Statistical analysis was done by ANOVA and statistical significance was defined as P <0.05. RESULTS: Group M and MP showed significantly increased airway pressures compared with group C (P <0.05), but there was no difference among the groups in terms of viscoelastic pressure. Arterial blood gas analysis showed that group P and MP had lower arterial partial oxygen pressures than group C (P <0.05). CONCLUSIONS: This study demonstrates that the intratracheal administration of PFC in a bronchoconstriction cat model increases airway pressure more than tissue viscoelastic pressure, and decreased arterial oxygen partial pressure. We conclude that the intratrachel administration of PFC is not to be recommended in bronchoconstrictive situations.